Seasonal abundance of stable flies (Diptera: Muscidae) on California dairies.

Abstract

Abundance of the stable fly, Stomoxys calcitrans (L.), was studied on six Tulare County, Calif., dairies from April to July 1985 and on six Riverside County, Calif., dairies from April 1985 to July 1986. Stable flies were common from late April through June in both areas, and the house fly, Musca domestica L., was predominant in late summer and fall in Riverside County. Stable fly sticky trap catches averaged <400 flies per trap during peak prevalence in 1985 (drought year), but exceeded 500 flies per trap for 3 wk in 1986. Stable flies on cattle exceeded four flies per leg for 3–5 wk in 1985 and exceeded six flies per leg for 6–10 wk in 1986. Herd average leg counts >25 flies per leg were common in 1986 during peak abundance. Stable flies seem to be an important seasonal problem on California dairies.